It is known in the art that several engineering problems are related in one way or another to the simple requirement of governing or slowing a weight of any kind. These problems occur when there is a need to control the speed of the weight which is deprived of a driving (or “counterbalancing”) mechanism. Generally, such a situation occurs when the driving mechanism is not designed to control the speed in both directions or when there is an emergency situation or failure of the mechanism. Sometimes, driving mechanisms are not totally fail safe by design.
It is also known in the art that a fail safe mechanism or device is going to react in such a manner that, in a case of emergency or internal failure, the weight is going to move to a safe position at a controlled rate. Several mechanisms or devices are actually devised to brake and/or stop the weight they are meant to move, at the last known position before failure of the mechanism. Very often, such a behavior is not acceptable for many devices and mechanisms because a weight several feet above ground is still subject to fall if the link of the device or mechanism fails, and, if it is the case, there is nothing to stop or control the falling of the weight.
U.S. Pat. No. 4,432,254 granted to SCHULTZ on Feb. 21st, 1984, relates to a viscous damper having rigid plastic structure. This viscous damper which has any one or more of three main features, namely at least one of a rotor and housing being formed from rigid plastic material, a bearing projection on one housing portion extending from the plane of the housing working surface less than shear film spaced relation toward the working surface of the rotor member, and means for closing a filler opening through the housing comprising a sealing disk engaging on a shoulder across the opening and a retainer pressing the disk onto the shoulder and having radial retaining teeth, retainingly engaging a wall about the opening.
A problem associated with this type of viscous damper is the fact that it is not adjustable in real-time and it is not autonomous or disc-brake controlled by an electronic device with a feedback system to produce a governor-like behavior. Furthermore, another problem associated with this type of viscous damper is the fact that it requires an external source of power and is more complex than other governor devices.
Also known in the art are the following U.S. patents and patent applications which describe various devices for use with rotational shafts: U.S. Pat. Nos. 5,022,452 (Burrell); U.S. Pat. No. 5,421,221 (Warchocki); U.S. Pat. No. 5,634,507 (Kwoka); U.S. Pat. No. 6,059,008 (Yoshida et al.); U.S. Pat. No. 6,123,134 (Thomas et al.); U.S. Pat. No. 6,129,131 (Colson); U.S. Pat. No. 6,155,328 (Welfonder); U.S. Pat. No. 6,223,802 B1 (Colson); U.S. Pat. No. 6,443,210 B1 (Welfonder); 2002/0179258 A1 (Welfonder); and 2003/0024658 A1 (Beaudoin et al.).
Also known in the art are the many problems associated with these types of devices, which are related to the design of any governing mechanism, that is intended to be totally fail safe, examples of which are the following: the limited space available to implement the governing device; the need of feedback mechanisms to adjust the speed rate; the constant torque given by the braking device; the lack of mechanism that gives high torque in function of the speed rate; the lack of easy and real-time adjustment in the governing device; and the relative high cost of such devices. Hence, a big challenge essentially lies is resolving these different aspects with a single integrated system.
Hence, in light of the aforementioned, there is a need for an improved governor device which would be able to overcome some of the aforementioned problems.